Visiting Ethiopia for a short holiday - where should I go?

Hello all, I know there are many beautiful places to see. However, I will only have 10 or fewer days in the country. Also, domestic flights in Ethiopia are very expensive, so I cannot afford to visit all of the famous places by plane. Addis doesn't seem popular as a tourist attraction, but I love to see the capital, and I enjoy the hustle and hustle. From what I know, Lalibela is almost a must see! How about the other places? Which should I choose? Gondar? Axum? Another place? Also, how long would you recommend for each place? I think 3, absolute maximum of 4 places would possible. These must include Addis and Lalibela. Thank you